Question

cos²theta - sin²theta=1-tan²theta
1+tan²theta
​

Answer 1

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Hii friend,

Let @ be a theta.

Putting @ = 30° , we find

LHS = (Cos²@ - Sin²@)

= [(✓3/2)² - (1/2)²] = (3/4-1/4) = 2/4 = 1/2

RHS = 2tan30°/ 1 - tan²30°

= 2×1/✓3/[1-(1/✓3]² = 2/✓3/ 1-1/3 = 2/✓3 × 3/2 = ✓3.

THEREFORE,

LHS IS NOT EQUAL TO RHS.

HENCE,

THE GIVEN EQUATION IS NOT AN IDENTITY.

HOPE IT WILL HELP YOU.... :-)

Answer 2

$\huge\underbrace\mathfrak \red{ANSWER }$

Let @ be a theta.

Putting @ = 30° , we find

LHS = (Cos²@ - Sin²@)

= [(✓3/2)² - (1/2)²] = (3/4-1/4) = 2/4 = 1/2

RHS = 2tan30°/ 1 - tan²30°

= 2×1/✓3/[1-(1/✓3]² = 2/✓3/ 1-1/3 = 2/✓3 × 3/2 = ✓3.

THEREFORE,

LHS IS NOT EQUAL TO RHS.

HENCE,

THE GIVEN EQUATION IS NOT AN IDENTITY.

HOPE SO IT WILL HELP.....

PLEASE MARK IT AS BRAINLIST......